1. Field of the Invention
This invention relates to an acceleration sensor for vehicle-sensitive systems which is mounted on a part connected to the vehicle and comprises a mounting part having a baseplate, which has a spherical socket-shaped recess and bearing means for an impulse lever, which between the tip thereof and the part thereof mounted in the bearing means is enlarged to form a spherical socket-shaped cap. A ball which constitutes an inert; a mass is provided between the cap and the socket-shaped recess and an actuating member, which preferably consists of a control pawl which is in contact, or almost in contact with the tip of the impulse lever and is activated by the tip thereof as the ball is moved out of its position of rest by accelerations having predetermined values.
2. Description of the Prior Art
Such an acceleration sensor which is connected to a belt retractor is known from Published German Application 34 18 378. A satisfactory function of such acceleration sensor is ensured unless the baseplate of the mounting part for the ball is in a horizontal, or substantially horizontal, position. The acceleration sensor is usually adjusted to respond to accelerations in excess of 0.5 g. When the baseplate of the mounting part of the acceleration sensor assumes an inclined position, the ball will shift from its position of rest and the impulse lever will actuate the control pawl so that it enters between teeth of a control wheel and the belt retractor will thus be blocked.
If the acceleration sensor is connected to a part which is fixed to the vehicle and does not change its position relative to the vehicle, the baseplate of the mounting part will always remain in its predetermined horizontal basic position. However, if the belt retractor is installed, for instance, in the backrest of a seat of the vehicle and the position of the backrest is changed, the acceleration sensor will not be operable unless the baseplate of the mounting part is readjusted to a horizontal position.
German Patent Specification 26 58 747 discloses a seat belt system which is integrated in a seat, or a rest of a seat, of a motor vehicle and which, after a change of the position of the seat, or of the rest of the seat, can be adapted to the new position since the belt retractor provided with the acceleration sensor is mounted on a pivoted carrying plate, which through linkages consisting of levers and rods and/or Bowden cables can be pivotally moved to a position in which the vertical axis of the vehicle-sensitive blocking means is held in the direction of acceleration which is due to gravity. However, such known seat belt system involves a high expenditure because extensive adjusting and linkage means must be provided, which after any change of position of the seat or rest adjust the belt retractor provided with the acceleration sensor and in any adjusted position fix the belt retractor, so that it can take up the forces exerted by the belt.
From German Utility Model Specification 85 03 541 it is known per se to provide a belt retractor which is provided with an acceleration sensor which is secured to a seat of a vehicle and to adjust only the acceleration sensor rather than the entire belt retractor after a change of position of the seat. In such known adjusting mechanism, the lever which is described as an impulse lever directly constitutes a blocking lever for the control wheel so that when the blocking lever is actuated by the ball the tip of the lever will directly enter between teeth of a control wheel to block the same. However, because in the known apparatus the pivotal axis of the mounting part does not extend through the region of the tip of the blocking lever, any adjustment of the mounting part displaces the tip of the blocking lever relative to the teeth of the control wheel, so that an unchanged reliable movement of the blocking lever to a position between the teeth of the control wheel will no longer be ensured after a change of position.